1. Field of the Invention
The present invention relates to an electronic component mounting apparatus and an electronic component mounting method for mounting electronic components onto a substrate.
2. Description of the Related Art
Most electronic component mounting apparatuses that are used currently image electronic components held by a mounting head so as to recognize holding positions of the electronic components or the like, before the mounting head mounts the electronic components picked up from a part feeder on a substrate. In addition, when imaging the electronic components, lighting is applied to the electronic components. Furthermore, as a camera used for imaging the electronic components, a line camera or a 2D camera is used.
Although the line camera can be used to from small electronic components to large electronic components, lighting thereof is limited. That is, it is impossible to switch the method to apply lighting to the electronic components in the process of single mechanical scanning using the line camera. For this reason, in order to apply lightings of different forms to one electronic component to obtain an image, there is a need for two or more mechanical scanning. Furthermore, in order to image a large electronic component using the line camera, there is a need for a number of imaging elements capable of covering a maximum length of the electronic component. However, the greater the number of imaging elements, the longer a scanning time of the line camera. For this reason, when using the line camera also available for a large electronic component, it takes time for single mechanical scanning, and thus a speed of taking the image is limited. Furthermore, a constant speed scanning is essential, and there is a need to scan the line camera in a direction perpendicular to a line of the imaging elements owing to one-dimensional scanning.
A plurality of imaging elements of different sizes is prepared for a 2D sensor, and the imaging elements used for imaging are switched depending on the sizes of the electronic components. However, a head of the 2D sensor does not correspond to a configuration of a two line nozzle. In order to correspond to the configuration of the two line nozzle, there is a need to prepare two imaging elements for a small electronic component and one imaging element for a large electronic component. That is, it is necessary to achieve a camera constituted by three imaging elements on the same visual field. According to the configuration, if the imaging element for the large electronic component is achieved by the imaging element arranged in a line form, the scanning time becomes a problem, and if the imaging element for the large electronic component is achieved by the imaging element arranged in an area form, the cost thereof and a reading time of image data become a problem.
In the conventional art, in component inspection using a three-dimensional image such as in coplanarity inspection of leads of a QFP (Quad Flat Package) in the electronic component mounting apparatus, a type using a laser beam and a position detection element (PSD) described in Japanese Patent No. 3578588 has been mainly used. This type is basically different from the type using the camera for imaging the two-dimensional image in methods of the lighting and the imaging. For this reason, when adopting the type using the two-dimensional image, since both means for two-dimensional imaging and means for three-dimensional imaging have been provided in the electronic component mounting apparatus, there has been a great demerit in view of a size and costs of the electronic component mounting apparatus. Furthermore, essentially, in order to measure heights of the electronic components through the irradiation of the laser beam, although there is a need for a mechanical operation of the laser beam using a polygon mirror, the scanning time of the laser beam is limited. For this reason, it has been unsuitable to apply the type using the laser beam and the PSD to a production line for a chip component such as a resistor or a capacitor that is required to be mass-produced and speeded up, or a production line in which a strict takt time is required.
As other conventional arts, there are Japanese Patent No. 3336774, Japanese Patent No. 3318146, Japanese Patent No. 3341569, and Japanese Patent No. 3893184.